Tools by Trade

Ask Irwin

When would I use a tap and die set and how would I properly use them?

Tap and dies are metal threading tools. Taps make internal threads inside a hole and dies make external threads on a round rod. They are often used for rethreading (cleaning up existing threads).

HOW TO USE A TAP1a) To create new threads inside a hole you must first redrill the existing hole. Refer to the tap / drill chart in your set to determine the correct drill bit size for the new hole. Drill your new hole.

2a) Place the square of the tap into the tap holder and tighten. Place the tip of the tap into the hole. Keep the tap as perpendicular to the hole as possible. Press down and turn the tap in the hole. The tap should begin cutting threads into the wall of the hole. After making 2 - 3 full turns, turn the tap backwards 1/2 - 3/4 of a turn. This will break the chip loose.

3a) Continue the above steps until finished.

Dies are used in the same manner except they are used on a round rod instead of in a drilled hole. The die size you select should be the same size as the rod. IE If you want a 3/8" rod, you would use a 3/8" die.

We always recommend using a quality cutting fluid. This will extend the life of the tools and improves the quality of the threads.